1. Field of the Invention
This invention relates to diskette sequential transport apparatus. It relates more particularly to apparatus for transporting diskettes from a stack one after the other to a disk drive where each diskette may be evaluated or certified or otherwise operated on. The apparatus then transports each diskette from the disk drive to any one of a number of receiving locations.
The magnetic diskettes handled by the present apparatus, known in the trade as floppy disks, comprise a plastic or cardboard envelope inside of which is positioned a flexible magnetic disk. One such diskette of this general type is disclosed in U.S. Pat. No. 3,668,658. The diskettes come in a plurality of sizes, the most common having a five and one-quarter and an eight inch disk.
2. Description of the Prior Art
There already exist various apparatus for handling and transporting diskettes. U.S. Pat. Nos. 4,173,427 and 4,226,570 disclose transports for pulling diskettes from a magazine to a final position at which data transfer may take place, after which the diskette is returned to the magazine. In that prior machine, the diskettes have to be arranged in the magazine on edge. Clothespin type grippers clamp onto the diskette and pull the diskette from the magazine to the disk drive. After competion of the read or write operation, the diskette is transported back to its original location in the magazine.
That apparatus includes no provision for sorting the diskettes depending upon their performances in the disk drive. Also the transporting of each diskette to the read/write location using pulling clothespin-type grippers is not the most desirable way of achieving accurate positioning of the diskette in the disk drive. Rather, it would be preferable if such apparatus mimicked the action of a human when so positioning the diskette. That is, when loading a diskette manually, the operator invariably pushes against the rear or trailing edge of the diskette with his finger or thumb. Such pushing motion against the stiffest part of the cassette assures that the diskette is seated firmly and properly in the disk drive without damage to the diskette. To withdraw the diskette from the drive, the operator usually grips the edge of the diskette with his thumb and forefinger and pulls it out of the drive. Instead of handling the diskette in that customary way, that prior transport does just the reverse.
U.S. Pat. No. 4,195,321 discloses transport apparatus comprising a loading stacker and a receiving stacker mounted alongside a disk drive. A selectively operable slider transfers each diskette one at a time from the loading stacker to the disk drive and also retrieves each diskette from the disk drive for conveyance to the receiving stacker. That prior apparatus is relatively complicated comprising, as it does, numerous levers and cranks to effect the proper movement of the diskettes. Moreover, it requires dual drives, one for loading and one for stacking. Also, it has no provision for sorting the diskettes following their treatments at the read/write location; the diskettes are all routed to the same receiving stack.
The prior apparatus disclosed in the aforementioned patents have other drawbacks as well. As far as can be determined, they can only handle a single size diskette. Also, such apparatus must be mounted in juxtaposition to the associated disk drive so that the diskettes can be transported to and retrieved from the disk drive in a reliable fashion. Once mounted and aligned with a particular drive, it becomes difficult to maintain or repair that drive in the event of a malfunction or to replace the drive if that becomes necessary.
These and other apparatus of this general type of which we are aware are disadvantaged also in one or another of the following respects: they are excessively complicated and expensive, they are difficult to make and to maintain properly, and their operation is not as reliable as might be desired.